1. Field of the Invention
The present invention relates to a processing system that uses a carrying (containing) box capable of hermitically holding an object to be processed, such as a semiconductor wafer.
2. Description of the Related Art
Generally, when fabricating a semiconductor integrated circuit, such as an IC or a LSI device, a semiconductor wafer is subjected repeatedly to film deposition processes, oxidation-enhanced diffusion processes, etching processes and so on. The semiconductor wafer needs to be transferred from one to another one of those systems for carrying out those processes. As generally known, contamination of the surface of the semiconductor wafer with particles and formation of an oxide film by natural oxidation on the surface of the semiconductor wafer must be avoided in order to process the semiconductor wafer at an improved yield. Thus, there is a growing tendency to use a carrying box capable of sealing wafers therein for carrying wafers with the progressively growing device miniaturization and level of integration.
As shown in FIGS. 6 to 8, a conventional carrying box 502 for carrying semiconductor wafers W has a box body 506 having an open front side 504 and a substantially semicircular side wall. Supporting projections 508 are arranged at vertical intervals on the inner surface of the box body 506. Peripheral parts of semiconductor wafers W are supported on the supporting projections 508 so that the semiconductor wafers W are contained in a tier-like manner at substantially equal intervals in the box body 506. Usually, twenty-five or thirteen semiconductor wafers W are contained in the carrying box 502.
A square, hollow, flat lid 510 is detachably attached to the box body 506 so as to cover the open front side 504 of the box body 506. The box body 506 is properly sealed to maintain an atmosphere of an inert gas, such as N2 gas, therein so that the wafers W contained in the box body 506 are prevented from contacting the atmosphere as far as possible.
The lid 510 is provided with two locking mechanisms 512. The lid 510 can be removed from the box body 506 to open the open front side 504 by releasing the locking mechanisms 512.
More concretely, each of the locking mechanisms 512 has a locking bolt operating plate 514 having the shape of a disk and turnably supported on the lid 510 at a substantially middle position with respect to the height of the lid 510. The locking bolt operating plate 514 is provided with a slot 516. Circular motion of the locking bolt operating plate 514 is changed into linear motion of locking bolts 520 by crank mechanisms. One end of a link 518 is pivotally connected to the locking bolt operating plate 514, and the other end thereof is pivotally connected to one end of the locking bolt 520. When the locking bolt operating plate 514 is turned through an angle of 90xc2x0, in opposite directions, the locking bolts 520 are vertically moved between a locking position and an unlocking position.
As shown in FIGS. 6 and 7, free end parts of the locking bolts 520 can be engaged (inserted) in slots 522 formed in the upper and the lower section of the rim defining the open front side 504. In FIG. 7, only the slots 522 formed in the lower rim are shown. When the locking bolts 520 are engaged in the slots 522 with the lid 510 set in place on the box body 506 so as to cover the open front side 504, the lid 510 cannot be removed from the open front side 504.
The locking bolt operating plate 514 at a locking position shown in FIG. 8(a) can be turned through an angle of 90xc2x0 to an unlocking position shown in FIG. 8(b) by means of a lock operating member, not shown, engaged in the slot 516 of the locking bolt operating plate 514. Consequently, the locking bolts 520 can be retracted by a distance xcex94L from the slots 522 (FIG. 7) in order to unlock the lid 510.
Generally, the carrying box 502 is carried automatically in a processing system that includes: an automatic carrying-box carrying mechanism, a storage area for temporarily storing the carrying box, processing units for actually conducting predetermined processes to semiconductor wafers, and the like. The lid 510 of the carrying box 502 is automatically locked and unlocked by an automatic machine provided with the lock operating member according to the aforesaid procedure and is put on and removed from the box body 506 automatically.
Such processing systems are disclosed in, for example, JP-A No. Hei 4-180213 and Japan Patent Appln. No. Hei 11-201000 (patent application previously made by the applicant of the present patent application). An inert gas, such as N2 gas, or clean air with a high cleanliness is supplied into those systems.
The lid 510 may be removed temporarily to obtain information about the semiconductor wafers contained in the carrying box 502 before carrying the carrying box 502 into a processing system. Then, a mapping operation may be carried out to confirm the positions of the wafers and/or an identifying inspection may be carried out to identify the individual wafers.
Whereas the cleanliness of the atmosphere surrounding the processing system is on the order of class 10000, the interior of the processing system is maintained at a very high cleanliness on the order of class 1. Particles are prevented from entering the processing system.
In the conventional processing system, in a clean atmosphere, the lid 510 is temporarily removed from the box body 506 of the carry box 502 and operations for acquiring information about the semiconductor wafers, such as a mapping operation, is carried out. Although the operations including the mapping operation are carried out in the clean atmosphere of a high cleanliness, there is a tendency that problems often arise because particles deposited on the outer surface of the carrying box 502 in an atmosphere of a low cleanliness, such as a class 10000 atmosphere, may enter the carrying box 502 and adhere to the wafers when the lid 510 is removed.
Solution of such problems is desired particularly in recent years where the miniaturization of semiconductor devices has progressed to use semiconductor integrated circuits including lines of a submicron width and diameter of semiconductor wafers has increased from 6 in. via 8 in. to 12 in.
In addition, since a table for supporting a carrying box is placed in a housing in a conventional vertical heat treatment apparatus, the carrying box cannot be transferred between the table and an overhead conveying device supported on the ceiling of a clean room, that is, it is difficult to use the overhead conveying device. In a single-wafer processing apparatus that processes wafers one by one, a table may be disposed on the outer side of a gate to enable transferring a wafer between the table and an overhead conveying device. However, since the lid of the carrying box is removed on the table and the wafer is taken out of the carrying box, this arrangement cannot be applied to batch processing.
The present invention has been made in view of the foregoing problems to solve those problems effectively. Accordingly, it is an object of the present invention to provide a processing system using a carrying box for holding an object to be processed therein provided with a lid and capable of preventing the entrance of particles adhering to the outer surface of the carrying box into the carrying box when the lid is removed.
Another object of the present invention is to provide a processing system capable of using an overhead conveying device and of carrying out a batch-type process.
According to the present invention, a processing system for an object to be processed includes: a housing defining a closed space, the housing provided with an opening through which an airtight carrying box is carried in and out, the carrying box hermetically containing therein the object to be processed and provided with a detachable lid; a lid operating mechanism disposed near the opening to open and close the lid of the carrying box; and a contamination preventing duct capable of covering a space around the lid of the carrying box and of supplying a clean gas of a high cleanliness therein at least when the lid of the carrying box is opened.
According to the above feature, when removing the lid of the carrying box, the lid is covered with the duct and the clean gas of a high cleanliness flows through the duct. Thus, entrance of particles adhering to an outer surface of the carrying box into the temporarily opened carrying box can be prevented.
Preferably, a blower is disposed near the opening to blow the clean gas of a high cleanliness into the contamination preventing duct.
Preferably, a filter means is disposed near the opening to filter a gas to produce the clean gas of a high cleanliness.
Preferably, the blower and the filter means are mounted on a common frame, and an outlet end of the frame is spaced a short distance apart from the contamination preventing duct.
Preferably, the contamination preventing duct is capable of being moved vertically between a working position where the contamination preventing duct covers the lid and a waiting position apart from a path along which the carrying box moves.
Preferably, an information acquiring means that acquires information about the object to be processed contained in the carrying box is disposed near the opening.
Preferably, the information acquiring means is capable of being moved vertically between an information acquiring position where the information acquiring means faces the carrying box and a waiting position apart from a path along which the carrying box moves.
Preferably, the contamination preventing duct is adapted to cover the space around the lid of the carrying box and the clean gas of a high cleanliness is adapted to flow through the contamination preventing duct when the information acquiring means functions to acquire information about the object to be processed contained in the carrying box.
Thus, the lid is opened and closed and the information acquiring means operates for information acquisition in the contamination preventing duct through which the clean gas of a high cleanliness flowing. Accordingly, the entrance of particles into the carrying box can be substantially perfectly prevented even if particles are scattered because the clean gas carries the scattered particles away.
Preferably, a storage unit for temporarily storing the carrying box therein is installed in the housing.
Preferably, a processing unit for conducting a predetermined process to the object to be processed contained in the carrying box is installed in the housing.
In addition, according to the present invention, a processing system for an object to be processed includes: a housing defining a closed space, the housing provided with an opening through which an airtight carrying box is carried in and out, the carrying box hermetically containing therein the object to be processed and provided with a detachable lid; a conveying mechanism installed in the housing for conveying the carrying box; a table disposed outside the opening for supporting the carrying box thereon; and a moving mechanism provided at the table for moving the carrying box to a transfer position where the carrying box can be transferred to the conveying mechanism.
The processing system with the above feature enables the use of an overhead conveying mechanism or the like and batch-type processing, and enhances processing ability.
Preferably, the moving mechanism includes a fixing mechanism for temporarily fixing the carrying box. The fixing mechanism prevents the carrying box placed on the table from being carried away mistakenly by the operator.
Preferably, two moving mechanisms are incorporated into the one table. Preferably, the two moving mechanism are capable of laterally moving toward a center therebetween.
Thus, the two moving mechanisms can be positioned in a narrow operating range of the conveying mechanism, and the processing system can be formed in compact construction, and throughput of the processing system can be enhanced.
Preferably, a lid operating mechanism for opening and closing the lid of the carrying box is incorporated into the table.
Preferably, an information acquiring means that acquires information about the object to be processed contained in the carrying box is incorporated into the table.
Preferably, an electrical unit is disposed below the transfer position where the carrying box can be transferred from the moving mechanism to the conveying mechanism.
Such disposition of the electrical unit facilitates arrangement of cables and enables the processing system to be formed in compact construction.